Why does music in my car stereo sound distorted and bad?

Recently I bought a new car, its a 2014 Nissan Versa Note, the fully loaded model. It came with a USB/AUX spot. When I connected my Iphone into the USB slot my music played but it was terrible quality when I turned up the volume and bass. When the Bass was at 3 out of 10 and the volume was about 1/3 up it was ok but when I turned up the volume and bass (I like my music loud) to above 5/10 bass or 1/2 max sound it sounded distorted and far away. It was as if someone was blowing into the speaker or like those old TVs had that white noise that went pssssssst. This problem only arises when I turn the volume and/or bass up.
I bought an AUX cable thinking that would help but it didn't help at all. Than I tried to connect my phone via the Bluetooth installed in the car, and while the music sounded a lil better it was still bad. I tried this with my Iphone and android and still the same problem.
Finally I decided to burn a Data CD. For the first 20ish minutes the songs played great, the volume was clear and it didn't get distorted when I cranked up the bass so loud the car was shaking. When I left my car at the mall and came back 15 minutes later, the sound was again distorted even on the same songs. I don't know what happened. This is a brand new car I bought 2 months ago. I thought the songs were poor quality so I tried the CD in my other car (2005 Mercedes ML350) and it worked perfectly even on max bass and volume. Does Nissan make shitty speakers or what's the issue?

Its under warranty…

Dude. It's stock. Stock is **** no matter the maker unless the car comes with Bose. If you want a good sounding system, replace the speakers with Pioneer 3-way mid-woofers off of Amazon for $60 a pair. They have all sizes so find out what your car takes. These mid-woofers, when tuned right, can actually sound like you have a 10" in the back but you can't put them too loud considering they are just mid-woofers. Still very good sound quality. You want bass, get a 1000w Pyramid 2-channel amp and either one or two Kicker Comp 4ohm 300w subs and a box with at least 1.5 cu. Ft. Per chamber sealed and put it in the back. All of this is on Amazon. Subs are $60 each and the amp is like $55. Boxes run $30-$60 depending on several variables. Don't bother with more expense, just get a low-dollar one and if it has leaks, buy some sealant foam from a hardware store.

Now, if this doesn't fix you're problem with the white noise, it's your head unit which can be replaced under warranty I'd assume or you can buy an after market, up to you. But either way, throw out that stock **** and get the system I just detailed. Not very expensive but sounds beautiful when tuned properly. Comment on this answer if you'd like help with tuning because I currently own this system and I have two subs, started with one, so I can help you tune for both options.

I would try using the stock speakers for highs and a few mids, but it sounds like they can't take bass very well, and again, there cheap. That being said, try turning down the bass to see if it sounds ok, if so, try to get a small sub for the lows.

The music sounds different coming from Wi-Fi why?